The CFUR settings cause an interesting behavior when the remote office is not in SRST mode. Support that a phone is unplugged.
The CUCM sees the phone as unregistered. If someone calls the directory number, the CUCM sends the call out to the PSTN and when the remote gateway
gets the call, it forwards it back to headquarters which sends it to the PSTN. A call that loops until all resources are exhausted.
Solution is to set the “Max Forward UnRegistered Hops to DN” service parameter. The default is 0 (unlimited), but a value of 2 should work
in most situation.
Demystify and Simplify 